Wire stripping tool

Description

[0001] This invention relates to wire stripping tools used for removing or displacing a portion of the sheath or covering from a wire core, for example in preparing an insulated electrical conductor for connection.

[0002] British Patent No. 1110935 discloses a range of wire stripping tools comprising a pair of outer jaws for gripping the sheath or covering, a pair of inner jaws located between the outer jaws for cutting into the sheath or covering, and a pair of handles which can be closed together so as to first close both pairs of jaws and then displace the inner jaws relative to the outer jaws, so as to move the cut portion of the sheath along the core. As mentioned in said Patent, the cut into the sheath need not be completed in that the displacing movement can tear the sheath so as to achieve a like effect.

[0003] In British Patent 1164184 a lever handle closes the jaws and the inner cutting jaws are displaced for the stripping by a rod or drawbar. The handle is connected to both the jaw and the drawbar by a whole system of links forming two sets of toggle linkages acting respectively between the handle and jaw, and between the handle and drawbar. This is complex to make and assemble and the geometry is critical.

[0004] The problem with wire stripping tools of this kind is to produce a simple design capable of economical manufacture and which can cope with a range of different cables and the like, which may differ from one another in terms of overall thickness, core thickness, and sheath hardness.

[0005] The object of the present invention is to provide an improved tool for these purposes.

[0006] In accordance with the invention a wire stripping tool comprises a pair of outer jaws for gripping a cable, at least one of the outer jaws being pivotally mounted on a relatively stationary part, a pair of inner jaws for cutting the sheath of the cable, a lever handle for closing the jaws, a drawbar connected to the inner jaws, a spring resisting movement of the drawbar, and at least one link pivoted to the handle and to the drawbar for displacing the inner jaws relative to the outer jaws, and is characterised in that the pivot of said at least one outer jaw is between the ends of the jaw, and that an end of the jaw is pivoted to the end of the lever handle, handle closing movement causing jaw closing whilst drawbar movement is resisted by spring pressure and when jaw closing ceases due to resistance of the cable, the spring deflecting to allow drawbar displacement by the handle via the said link.

[0007] The invention will be better understood from the following description of a presently preferred embodiment wherein the sole figure is a part sectional elevation of a wire stripping tool.

[0008] The tool shown in the drawing comprises a pair of outer jaws 10 for gripping the sheath or covering of a cable, and a pair of lever handles 12. The handles are pivotally connected to the jaws by pins 14 which also serve to fulcrum first links 16, these links 16 being pivoted at their other ends upon pins 18 to a cursor 20.

[0009] The outer jaws 10 are also pivoted on pins 22 which pass through a relatively stationary part in the form of a pair of mounting plates or common member which lie in parallel planes and extend from the vicinity of the pins 22'to surround pin 24.

[0010] A pair of cutting jaws 26 is located between the gripping jaws 10, and these jaws are spring- urged apart by a small compression spring 28, the cutting jaws being pivoted together on pin 30 which also couples the inner jaws 26 to a drawbar 32. The cursor 20 is a slide fit on the drawbar, and a second pair of links 34 is pivotally connected to the drawbar pins 36, the outer ends of these links 34 being pivotally connected to the lever handles 12 by further pins 38.

[0011] The drawbar is formed at the end opposite to pin 30 with a cutting edge 40, and this is arranged to slide past the second cutting edge 42 formed on a cutter plate held in position by pin 24.

[0012] The drawbar is conveniently formed with a pair of elongated and co-axial slots 44, 46 and a respective limit pin 48, 50 extends through each of these and also through the said metal frame plates. The pin 50 serves as an end abutment for a helically wound compression spring 54, the opposite end of which uses the second links 34 as an end abutment, so that this spring tends to drive the drawbar and hence the cutting jaws 26 to the illustrated position relative to the length of the gripping jaws 10. The pin 48, in addition to guiding the drawbar for linear displacement (as later described) also serves to provide a limit stop for movement of the cursor 20 towards the jaws.

[0013] In operation, the cable to be treated is placed between the jaws generally in the position indicated by the chain dot line 60 and then the levers 12 are closed towards one another. The initial movement of the lever handles 12 is to pivot them about the pins 38 so that the pins 14 separate, and take the pivotally coupled ends of the jaws 10 further apart, and because the jaws 10 are pivoted on the pins 22, this closes the gripping jaws upon the cable 60. At the same time, and because the first and second links 16, 34 lie at an acute angle to one another, the pins 18 move the cursor towards the jaws until the movement is terminated either by the resistance of the cable 60 preventing the jaws being closed further or by the cursor 20 contacting the limit pin 48. As well as the jaws 10 gripping the cable sheath, the cutting jaws 26 penetrate into the sheath.

[0014] Subsequent closing movement of the lever handles towards one another is effected with pivoting of the handles about the pins 14 so that the shallow obtuse angle between the two links 34 reduces, and hence the drawbar 32 is displaced against the spring 54 and the cutting jaws 26 are moved relative to the gripping jaws 10 so as to pull the end portion of the sheath along the core of the cable so as to bare the core. At the end of the operation, when the handles are released, the spring 54 and also the spring 28 return the parts to the illustrated position so that the cable can be removed and a fresh one treated.

[0015] The end of the drawbar provided with the cutting edge 40 runs in a generally tubular housing 62 having a lateral slot 64, so that a wire can be cut to length before stripped by being inserted in the slot 64 and the lever handles moved together so that the cutting edges 40, 42 move in scissor fashion to snip the cable.

[0016] In another embodiment of the invention (not illustrated) one of the jaws 10 is made integrally with the associated lever handle 12 and the corresponding links 16 and 34 are omitted. This unitary part may be made fast with the sleeve 62, and the operation then is exactly the same as described, except that the total closing movement possible for the jaws is only half of what would be the case with the illustrated tool. Such a tool is therefore useful for a narrower range of cable sizes.

[0017] In either version, the range of sheath to core ratios which can be treated satisfactorily can be increased by providing a screw adjuster effective to displace one of the cutting jaws 26- relative to its gripping jaw 10 so that the projection of the cutting edge 66 relative to the gripping face 68 can be varied.

Claims

1. A wire stripping tool comprising a pair of outer jaws (10) for gripping a cable, at least one of the outer jaws being pivotally mounted on a relatively stationary part, a pair of inner jaws (26) for cutting the sheath of the cable, a lever handle (12) for closing the jaws, a drawbar connected to the inner jaws, a spring (54) resisting movement of the drawbar, and at least one link (34) pivoted to the handle (at 38) and to the drawbar (32, at 36) for displacing the inner jaws relative to the outer jaws, characterised in that the pivot of said at least one outer jaw (10) is between the ends of the jaw, and that an end of the jaw is pivoted to the end of the lever handle (on pin 14), handle closing movement causing jaw closing whilst drawbar movement is resisted by spring pressure and when jaw closing ceases due to resistance of the cable, the spring deflecting to allow drawbar displacement by the handle via the said link (34).

2. A stripping tool as claimed in Claim 1 characterised in that only one gripping jaw (10) is pivotally connected as aforesaid, and the other is made integral and unitary with a lever handle (12).

3. A stripping tool as claimed in Claim 1 characterised in that both outer jaws (10) are pivotally connected to corresponding lever handles (12) and both lever handles are pivotally connected to links (34) connected to the drawbar.

4. A wire stripping tool as claimed in Claim 1 wherein a further link (16) is connected at one end, to the pivotal connection (14) between the jaw and lever handle and at the other end to a cursor (20) arranged so that initial closing movement of the pivoted handle displaces the cursor towards the jaws and increases the distance between the pivotal connection of the lever handle and jaw from the drawbar.

5. A wire stripping tool as claimed in Claim 1 wherein the drawbar is provided with a cutting edge (40) arranged to be displaced beyond a second cutting edge (42) in drawbar displacement.

Ansprüche

1. Drahtabisolierwerkzeug, enthaltend ein Paar äußerer Backen (10) zum Ergreifen eines Kabels, wobei wenigstens ein der äußeren Backen schwenkbar an einem relativ stationären Teil angeordnet ist, ein Paar innerer Backen (26) zum Schneiden des Kabelmanteis, einen Hebelgriff (12) zum Schließen der Backen, eine mit den inneren Backen verbundene Zugstange, eine der Bewegung der Zugstange entgegenwirkende Feder (54) sowie wenigstens ein Verbindungsglied (34), das an den Griff (bei 38) und an die Zugstange (32, bei 36) angelenkt ist, für eine Verlagerung der inneren Backen relative zu den äußeren Backen, dadurch gekennzeichnet, daß die Schwenkachse der genannten einen äußeren Backe (10) sich zwischen den Enden der Backe befindet und daß ein Ende der Backe schwenkbar am Ende des Hebelgriffes (am Zapfen 14) angeordnet ist, wobei eine Griffschließbewegung ein Schließen der Backe bewirkt, während einer Zugstangenbewegung durch den Federdruck entgegengewirkt wird, und wobei, wenn das Schließen der Backen aufgrund des Kabelwiderstandes aufhört, die Feder abgelenkt wird, wodurch die Zugstange durch den Griff über das genannte Verbindungsglied (34) verlagerbar ist.

2. Drahtabisolierwerkzeug nach Anspruch 1, dadurch gekennzeichnet, daß nur eine Greifbacke (10)-wie zuvor erwähnt-schwenkbar verbunden ist, während die andere einstückig und einheitlich mit einem Hebelgriff (12) ausgeführt ist.

3. Drahtabisolierwerkzeug nach Anspruch 1, dadurch gekennzeichnet, daß beide äußeren Backen (10) schwenkbar mit zugehörigen Hebelgriffen (12) und beide Hebelgriffe schwenkbar mit Verbindungsgliedern (34) verbunden sind, die mit der Zugstange in Verbindung stehen.

4. Drahtabisolierwerkzeug nach Anspruch 1, dadurch gekennzeichnet, daß ein weiteres Verbindungsglied (16) an einem Ende mit der Schwenkverbindung (14) zwischen der Backe und dem Hebelgriff und am anderen Ende mit einem Schieber (20) verbunden ist, der so angeordnet ist, daß eine anfängliche Schließbewegung des schwenkbaren Griffes den Schieber in Richtung auf die Backen verlagert und den Abstand zwischen der Schwenkverbindung des Hebelgriffes und der Backe von der Zugstange vergrößert.

5. Drahtabisolierwerkzeug nach Anspruch 1, dadurch gekennzeichnet, daß die Zugstange mit einer Schneidkante (40) versehen ist, die so angeordnet ist, daß sie bei einer Zugstangen-Verlagerung über eine zweite Schneidkante (42) hinaus verlagerbar ist.

Revendications

1. Outil pour dénuder des fils comprenant une paire de mâchoires extérieures (10) pour saisir un câble, l'une au moins des mâchoires extérieurs étant montée à pivotement sur une partie relativement fixe, une paire de mâchoires intérieures (26) pour couper la gaine du câble, une poignée formant levier (12) pour fermer les mâchoires, une tirette reliée aux mâchoires intérieures, un ressort (54) opposant une résistance au mouvement de la tirette et au moins une biellette (34) articulée à la poignée (en 38) et à la tirette (32 en 36) pour déplacer les mâchoires intérieures par rapport aux mâchoires extérieures, caractérisé en ce que l'articulation d'au moins ladite mâchoire extérieure (10) est entre les extrémités de la mâchoire et qu'une extrémité de la mâchoire s'articule à l'extrémité de la poignée formant levier (sur l'axe 14), le mouvement de fermeture des poignées provoquant la fermeture des mâchoires tandis que le mouvement de la tirette se heurte à la résistance de la pression de ressort et, quand le mouvement de la tirette cesse par suite de la résistance du câble, le ressort subissant une flexion pour permettre le déplacement de la tirette par la poignée par l'intermédiaire de ladite biellette (34).

2. Outil pour dénuder les fils selon la revendication 1, caractérisé en ce qu'une seule mâchoire de serrage (10) est montée à pivotement comme indiqué tandis que l'autre fait corps en une structure unitaire avec une poignée formant levier (12).

3. Outil pour dénuder les fils selon la revendication 1, caractérisé en ce que les deux mâchoires extérieures (10) s'articulent à des poignées correspondantes formant leviers (12) et que les deux poignées formant leviers sont reliées à des biellettes (34) raccordées à la tirette.

4. Outil pour dénuder les fils selon la revendication 1, dans lequel une autre biellette (16) est reliée à une extrémité à la liaison par pivotement (14) entre la mâchoire et la poignée formant levier et à son autre extrémité à un curseur (20) disposé de façon qu'un mouvement initial de fermeture de la poignée articulée déplace le curseur vers les mâchoires et augmente la distance entre la tirette et l'articulation de la poignée formant levier avec la mâchoire.

5. Outil pour dénuder les fils selon la revendication 1, dans lequel la tirette est prévue avec un bord de coupe (40) disposé pour être déplacé au-delà d'un second bord de coupe (42) par le déplacement de la tirette.

Drawing